Patent Application
20110290047
The present invention relates to devices and associated methods for producing seismic forces and, more particularly, to producing large repetitive forces using relatively lightweight vehicles.
It is often desirable to employ a relatively lightweight vehicle to generate a large, repetitive, seismic force for duties such as soil compaction and/or demining purposes. The seismic force must be generated while minimizing interference with the vehicle's handling, stability, and structural integrity. Furthermore, it is desirable that the mechanism that generates the seismic load be robust enough to withstand not only the relatively large repetitive force but, in the case of demining vehicles, also withstand blast events. It order to more efficiently utilize resources, it is also desirable that the mechanism used to generate the seismic force be a stand-alone accessory that is relatively easily transferrable between different vehicles.
The present invention provides an oscillator device employing two counter-rotating masses that generate a large impact force at multiple frequencies. In one embodiment of the device of the present invention the device has an oscillating mode and an impact mode. In another embodiment of the present invention the device has only an impact mode.
These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which:
Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.
The oscillator device of the present invention is operable to generate large ground impact forces at multiple operating frequencies without generating forces in other undesired orientations that could adversely affect dynamic stability and/or cause structural, fatigue-inducing vibration in the vehicle to which the device is attached. The oscillator device of the present invention is configured around two synchronized, counter-rotating masses that produce a force that is purely normal to the suspension arm when the arm is coupled to a drive motor. One advantage of the present invention is that the motion created by the oscillator is purely harmonic, thereby minimizing the amount of energy input to create the desired seismic signals.
In one embodiment of the present invention, shown in
When operating in oscillating mode, the lay shaft 15 drives a counter-rotation gearset 16. The counter-rotation gearset 16 simultaneously rotates an inner spindle 17 and an outer spindle 19 in opposite directions as indicated by arrows 9, shown in
Since the inner spindle 17 and the outer spindle 19 to which the oscillator mass 18 and the oscillator mass 20 are attached, respectively, are rotating in opposite directions, the oscillator masses 18 and 20 are also counter-rotated about the axis 8. In order to accommodated for the counter-rotation of the oscillator masses 18 and 20 within the confined space of the wheel 22, the oscillator masses 18 and 20 have rotate at different orbits about the axis 8. That is to say, the yokes attaching the oscillator masses 18 and 20 the spindles 17 and 19, respectively, secure the oscillator mass 18 at a different length from the axis 8 than the oscillator mass 20 is secured from the axis 8. For example, as shown in
Consequently, in order to maintain symmetry within the system, the masses of the oscillator masses 18 and 20 are unequal. The outer oscillator mass 20 is smaller than inner oscillator mass 18; however, in view of their different orbits about the axis 8, the oscillator masses 18 and 20 are proportionate to each other so that they both generate equal centripetal forces when rotated at the same angular velocity. The counter-rotation gearset 16 synchronizes the motion of both of the oscillator masses 18 and 20 such that they both rotate at the same angular velocity, one clockwise and the other counter-clockwise, and such that the oscillator masses 18 and 20 both reach their maximum vertical position simultaneously and their minimum vertical position simultaneously. When synchronized in this manner, the horizontal forces generated by each oscillator mass 18, 20 are equal and opposite the other oscillator mass 18, 20. Accordingly, the horizontal forces of the oscillator masses 18 and 20 cancel each other out and the device 5 effectively transmitting no horizontal forces to the vehicle to which it is attached. The vertical forces generated by the oscillator masses 18 and 20 are equal and additive, thereby producing a purely vertical resultant force.
When tractive effort is desired instead of oscillating forces, a dog clutch 23 is employed to disengage the lay shaft 15 from the counter-rotation gearset 16 and to engage the lay shaft 15 with a drive gearset 24. The driven gear of drive gearset 24 is mounted to drive shaft 25. Drive shaft 25 is affixed to outer wheel hub 26 which is in turn affixed to road wheel 22. As shown in
In a second embodiment of the present invention, shown in
The counter-rotation gearset 116 is similar to the counter-rotating gearset 16 described above for the device 5. The counter-rotating gearset 116 synchronizes the rotation of the inner oscillator mass 118 and the outer oscillator mass 119 about an axis 108 of the wheel 122 such that the inner oscillator mass 118 and the outer oscillator mass 119 both rotate at the same angular velocity, one clockwise and the other counter-clockwise and that both oscillator masses 118 and 120 reach their maximum vertical position simultaneously and both reach their minimum vertical position simultaneously.
Torque is transmitted to the inner oscillator mass 118 by an inner drive shaft 117 to which to inner oscillator mass 118 is affixed. Torque is transmitted to the outer oscillator mass 119 by an outer drive shaft 120. One or both of the oscillator masses 118 and 120 may be attached to their respective drive shafts 117 and 119 by yokes 121. The yokes 121 secure the oscillator mass 118, 120 to the drive shafts 117, 119 at appropriate distances from the axis of rotation 8.
Both the inner drive shaft 118 and the outer drive shaft 119 are concentrically aligned with the axis 108 and nested within at least one wheel spindle 124. At least one wheel bearing 126 is affixed to the road arm 110 and supports a wheel spindle 124, allowing it to freely spin about the axis of rotation 108. The wheel spindle 124 is affixed to at least one side plate 123, which is turn attached to the road wheel 122. The road wheel 124 transmits impact forces generated by the inner oscillator mass 116 and the outer oscillator mass 117 into the terrain being traversed by the vehicle.
In a third embodiment of the present invention, shown in
An oscillator housing 244 is affixed to at least one of the wheel spindles 240 such that the oscillator housing 244 does not rotate about an axis of rotation 208. The oscillator housing 244 includes a compartment 245 accessed by front cover plate 246. The compartment 245 contains a first oscillator gear 248 and a second oscillator gear 250. The first oscillator gear 248 is affixed to a drive shaft 249, and the second oscillator gear 250 is affixed to an auxiliary shaft 251. The first oscillator gear 248 and the second oscillator gear 250 mesh with one another such that when the first oscillator gear 248 rotates in the clockwise direction, the second oscillator gear 250 rotates in the counterclockwise direction.
As shown in
The first oscillator gear 248 and the identical second oscillator gear 250 each include at least one eccentric lightening hole 252. The eccentric lightening hole 252 serves to offset the center of mass of each gear from its pitch center, thereby causing the first oscillator gear 248 and the second oscillator gear 250 to act as synchronized, counter-rotating oscillator masses similar to those described above regarding the devices 5 and 105. The offset center of mass can be further increased by varying the size, number and location of lightening holes 252 and by employing one or more counterweights, not shown, opposite the holes 252. The counterweights may, for example, be attached to the first oscillator gear 248 and the second oscillator gear 250 gear by using counterweight mount holes 254. For the sake of clarity, it is noted that the rotation of road wheel 222 is independent of the oscillator motion.
The oscillator device of the present invention has a number of features which increase its resistance to damage, such as damage caused by a blast event resulting from detonation of a landmine. For example, in embodiments employing a drive chain or belt, the system is configured to accommodate large amounts of transient arm bending and torsional deflection produced during a blast event without becoming misaligned. Furthermore, the oscillator components are fully enclosed in the integral wheel hub and spindle or within the oscillator housing, thereby protecting them from foreign object damage and fully containing them within the wheel rim. A monolithic wheel not only keeps damaged oscillator components from causing damage to other vehicle components or bystanders in the work zone, it also acts as a natural shield to protect the rotating components from impact damage during a blast event and foreign object damage during operation in rough terrain.
Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.
This application claims priority to U.S. Provisional Application Ser. No. 61/330,239 filed Apr. 30, 2010, entitled OSCILLATING DEVICE FOR GENERATING SEISMIC LOADS AND COMPACTING SOIL, the contents of which are incorporated in their entirety herein.
| Number | Date | Country | |
|---|---|---|---|
| 61330239 | Apr 2010 | US |
